In the existing in-synchronization and out-of-synchronization determination under continuous packet connectivity (Continuous Packet Connectivity, CPC) discontinuous reception (Discontinuous Reception, DRX), a physical layer (also referred to as Layer 1, L1) of a user equipment (User Equipment, UE) performs in-synchronization and out-of-synchronization detection only on a valid radio frame of a slot (SLOT) of a fractional dedicated physical channel (Fractional Dedicated Physical Channel, F-DPCH), and reports the detection result to a high layer of the UE. According to an existing 3GPP (Third Generation Partnership Project) protocol, the high layer of the UE, upon receiving multiple (for example, N313) out-of-synchronization indications reported by the physical layer, starts a specific (number T313) timer. The high layer of the UE stops and resets the T313 timer if multiple (for example, N315) in-synchronization indications are received before the T313 timer expires; and determines that a current radio link fails if the T313 timer expires before N315 in-synchronization indications are received, which triggers corresponding radio link failure handling.
However, during a period where the T313 timer performs timing, all frames (that is, radio frames under a valid slot) under non-CPC DRX are valid, but not all frames under CPC DRX are valid where invalid frames (that is, radio frames under an invalid slot) exist. No in-synchronization and out-of-synchronization detection is performed within the invalid frames, resulting in that the duration of T313 and the number of counted in-synchronization indications do not increase proportionally (as shown in FIG. 1). Therefore, the existing in-synchronization and out-of-synchronization determination method based on non-CPC DRX is not fully proper for CPC DRX, and makes it more likely to determine a radio link failure.